Rosuvastatin intermediates and their preparation

ABSTRACT

Provided are processes and intermediates for preparation of rosuvastatin.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application No. 60/997,446, filed Oct. 2, 2007, and 61/126,638, filed May 5, 2008. The contents of which are incorporated herein by reference.

FIELD OF THE INVENTION

The invention relates to new synthesis of Rosuvastatin intermediates.

BACKGROUND OF THE INVENTION

Complications of cardiovascular disease, such as myocardial infarction, stroke, and peripheral vascular disease account for half of all deaths in the United States. A high level of low density lipoprotein (LDL) in the bloodstream has been linked to the formation of coronary lesions which obstruct the flow of blood and promote thrombosis. (See Goodman and Gilman, The Pharmacological Basis of Therapeutics, 9^(th) ed., p. 879 (1996)). Reducing plasma LDL levels has been shown to reduce the risk of clinical events in patients with cardiovascular disease and in patients who are free of cardiovascular disease but who have hypercholesterolemia. (Scandinavian Simvastatin Survival Study Group, 1994; Lipid Research Clinics Program, 1984a, 1984b.)

Statin drugs are currently the most therapeutically effective drugs available for reducing the level of LDL in the blood stream of a patient at risk for cardiovascular disease.

The mechanism of action of statin drugs has been elucidated in some detail. The statin drugs disrupt the synthesis of cholesterol and other sterols in the liver by competitively inhibiting the 3-hydroxy-3-methyl-glutaryl-coenzyme A reductase enzyme (“HMG-CoA reductase”). HMG-CoA reductase catalyzes the conversion of HMG-CoA to mevalonate, which is the rate determining step in the biosynthesis of cholesterol. Consequently, HMG-CoA reductase inhibition leads to a reduction in the rate of formation of cholesterol in the liver. Decreased production of cholesterol causes an increase in the number of LDL receptors and corresponding reduction in the concentration of LDL particles in the bloodstream. Reduction in the LDL level in the bloodstream reduces the risk of coronary artery disease. (J.A.M.A. 1984; 251: 351-74).

Currently available statins include: inter alia, compactin, lovastatin, simvastatin, pravastatin, fluvastatin, cerivastatin and atorvastatin, which are administered in their lactone form, as sodium salts, or as calcium salts.

Rosuvastatin (7-[4-(4-fluorophenyl)-6-isopropyl-2-(N-methyl-N-methylsulfonylamino) pyrimidin-5-yl]-(3R,5S)-dihydroxy-(E)-6-heptenoic acid) calcium, an HMG-CoA reductase inhibitor, can lower LDL-cholesterol and triglycerides levels more effectively than first generation statin drugs. Rosuvastatin calcium has the following chemical formula:

A number of processes for the preparation of rosuvastatin and salts thereof are disclosed. Rosuvastatin calcium, intermediates of rosuvastatin, and their preparation are disclosed in U.S. Pat. No. 5,260,440, herein the '440 patent. PCT publication No. WO 03/097614 discloses the synthesis of rosuvastatin from the late intermediate methyl (3R)-3-(tert-butyldimethylsilyloxy)-5-oxo-6-triphenyl-phosphoranylidene hexanate, an intermediate disclosed in the '440 patent. PCT publication No. WO 00/49014 discloses the synthesis of rosuvastatin using intermediates with other side chains via a Wittig reaction. EP 850,902 discloses the removal of triphenylphosphine derivatives in mixtures.

PCT publication No. WO 06/091771 describes the synthesis of rosuvastatin calcium according to the scheme provided below:

PCT publication No. WO 03/087112 discloses the synthesis of rosuvastatin from an intermediate t-butyl (3R)-3-(t-butyldimethylsilyloxy)-6-dimethoxyphosphinyl-5-oxohexanate (“19TBPO”). This process describes the preparation of t-butyl-7-[4-(4-fluorophenyl)-6-isopropyl-2-(N-methyl-N-methylsulfonylamino)pyrimidine-5-yl]-(3R)-3-hydroxy-5-oxo-6-heptenate (“TB21”), a key intermediate in the preparation of rosuvastatin, by going through 19TBPO intermediate. The process is illustrated in the following scheme:

Other intermediates and their preparation are also described in U.S. Pat. Nos. 5,354,879 and 5,717,124, which disclose the preparation of intermediate 19TBPO or ester analogs using purification by column chromatography

Like any synthetic compound, rosuvastatin calcium can contain extraneous compounds or impurities that can come from many sources. These can include unreacted starting materials, by-products of the reaction, products of side reactions, or degradation products. Impurities in rosuvastatin or any active pharmaceutical ingredient (API) are undesirable, and, in extreme cases, might even be harmful to a patient being treated with a dosage form of the API in which a sufficient amount of impurities are present.

There remains a need in the art for cost effective, industrial scale processes and shorter processes for the preparation of rosuvastatin intermediates.

SUMMARY OF THE INVENTION

In one embodiment, the present invention encompasses a non protected hydroxyl group intermediate, 19 OH-XYPO, having the following formula:

wherein X is O, N, or S, and Y is selected from the group consisting of: a C₁-C₄ alkyl, aryl, and alkyl aryl group, preferably 19 OH-TBPO, having the following formula:

In another embodiment, the present invention encompasses a process for preparing 19 OH-XYPO (particularly 19 OH-TBPO), comprising combining a compound, 19-OH-MBSG-XY, having the following formula:

preferably OH-MBSG, having the following formula:

dimethylmethylphosphonate (DMMP) and a base which is capable of making a carbanion on DMMP.

In another embodiment, the present invention provides a process for preparing 19 OH-XYPO (particularly 19 OH-TBPO) and further converting it to TB21 and/or rosuvastatin and pharmaceutically accepted salts thereof.

In another embodiment the present invention provides a compound, OH-MBSG-XY, having the following formula:

wherein X is O, N, or S, and Y is selected from the group consisting of: a C₁-C₄ alkyl, aryl, and alkyl aryl group, preferably OH-MBSG, wherein the compound has a purity of at least about 95.5% as measured by GC method.

In another embodiment, the present invention provides a process for preparing OH-MBSG-XY (particularly OH-MBSG) and further converting it to TB21 and/or rosuvastatin and pharmaceutically accepted salts thereof.

In another embodiment, the present invention also provides a process for purifying OH-MBSG and/or 19 OH-TBPO by using a thin film evaporator, more preferably a thin wiped-film evaporator

In another embodiment, the present invention encompasses a process for preparing compound TB21 by a Wittig-Horner reaction comprising combining 19 OH-XYPO (particularly 19 OH-TBPO), FPP-aldehyde and a base.

In another embodiment, the present invention encompasses a process for preparing TB21 having the following formula:

comprising combining OH-MBSG, dimethylmethylphosphonate (DMMP) and a base which is capable of making a carbanion on DMMP to obtain a non protected hydroxyl group intermediate 19 OH-TBPO; and combining the obtained 19 OH-TBPO with FPP-aldehyde and a base.

In another embodiment, the present invention a process for preparing TB21 and further converting it to rosuvastatin and pharmaceutically accepted salts thereof.

In another embodiment, the present invention a process for purifying a one or more of rosuvastatin intermediates 19 OH-XYPO of formula:

or OH-MBSG-XY of formula:

Wherein X is O, N, or S, and Y is selected from the group consisting of: a C₁-C₄ alkyl, aryl, and alkyl aryl group comprising applying a force under pressure of less than one atmosphere to increase surface area of a feed containing the intermediate, thereby providing the intermediate in purified form. In one embodiment the process comprises feeding the intermediate to a thin film evaporator is used. In one embodiment the process comprises feeding the intermediate to a thin film evaporator with wiper blades. Preferably X is O and Y is t-butyl.

In another embodiment, the present invention a process for preparing TB21 and further converting it to rosuvastatin and pharmaceutically accepted salts thereof.

DETAILED DESCRIPTION OF THE INVENTION

As used herein, the term “Wittig-Horner” refers to a condensation reaction of an aldehyde with a phosphonate derivative to create a double bond (also known as a Horner-Wadsworth-Emmons reaction). (See—Maryanoff et al. “The Wittig olefination reaction”, Chem. Rev. (1989) 89, 863-927; Boutagy et al. “Olefin synthesis with organic phosphonate carbanions”, Chem. Rev. (1974), 74 (1), 87-99; Wadsworth et al. “The utility of phosphonate carbanions in olefin synthesis”, JACS (1961), 83, 1733-1738; Tsuge et al. “Horner-Emmons Olefination”, Bull. Chem. Soc. Jpn. (1987), 60, 4091-4098.).

As used herein, the term room temperature (RT) refers to a temperature of about 20° C. to about 27° C.

As used herein, the term “OH-MBSG” refers to (R)-1-tert-butyl 5-methyl 3-hydroxypentanedioate having the following formula:

As used herein, the term “19 OH-TBPO” refers to the intermediate (R)-butyl 5-(methoxycarbino)-2-hydroxy-4-oxopentanoate having the following formula:

As used herein, the term “FPP-aldehyde” refers to 4-(4-fluorophenyl)-6-isopropyl-2-(N-methyl-N-methylsulfonylamino) pyrimidine, having the following formula:

As used herein, the term “TB21” refers to t-butyl-7-[4-(4-fluorophenyl)-6-isopropyl-2-(N-methyl-N-methylsulfonylamino)pyrimidine-5-yl]-(3R)-3-hydroxy-5-oxo-6-heptenate, having the following formula:

As used herein, the term “TBRE” refers to t-butyl-7-[4-(4-fluorophenyl)-6-isopropyl-2-(N-methyl-N-methylsulfonylamino)pyrimidine-5-yl]-(3R,5S)-3,5-dihydroxy-6-heptenate, having the following formula:

As used herein, “19 OH-XYPO” refers to the compound of formula:

wherein X is O, N, or S, and Y is selected from the group consisting of: a C₁-C₄ alkyl, aryl, and alkyl aryl group.

As used herein, “OH-MBSG-XY” refers to the compound of formula:

wherein X is O, N, or S, and selected from the group consisting of: a C₁-C₄ alkyl, aryl, and alkyl aryl group,

The present invention encompasses a non protected hydroxyl group intermediate, 19 OH-XYPO having the following structure:

wherein X is O, N, or S, and Y is selected from the group consisting of: a C₁-C₄ alkyl, C₆-C₁₂ aryl, and C₆-C₁₂ alkyl aryl group. Preferably X is O and Y is a C₁-C₄ alkyl group, more preferably, Y is a t-butyl ester, providing 19 OH-TBPO, with the following formula:

An actual NMR of this compound was taken that confirmed the presence of this compound. An approximate NMR of this compound is disclosed in the example.

19 OH-XYPO, particularly 19 OH-TBPO, is a key intermediate in the preparation of rosuvastatin calcium. The intermediate 19 OH-TBPO is a transparent to yellowish oil that cannot be purified by conventional scalable methods, such as crystallization.

In addition, 19 OH-TBPO decomposes at high temperatures of about 100° C., and therefore cannot be purified by conventional distillation. Removing the impurities by conventional distillation without causing decomposition would require maintaining 19 OH-TBPO under low pressure of less than about 0.3 mm Hg and high temperature of about 120° C. These requirements render conventional distillation methods inappropriate for the purification of large scale quantities of 19 OH-TBPO, and therefore conventional distillation of 19 OH-TBPO is not industrially applicable.

The invention provides a process for the purification of rosuvastatin intermediates, OH-MBSG-XY (particularly OH-MBSG) and/or 19 OH-XYPO (particularly 19 OH-TBPO), wherein the process is suitable for industrial use, as it does not entail chromatography steps. This process includes distilling the impurities of 19 OH-TBPO and OH-TBPO with a thin film evaporator (TFE) device. The lack of need for protection/deprotection makes the process much shorter.

The use of a thin film evaporator allows a temperature increase during the distillation process without decomposition of OH-MBSG-XY (particularly OH-MBSG) and/or 19 OH-XYPO (particularly 19 OH-TBPO), allowing the preparation of pure materials.

A typical thin-film evaporator comprises of two major assemblies: a heated body and a close-clearance rotor. A feed travels to a rotating distributor plate. The feed can be from the top, which would then fall naturally by gravity onto the plate.

Optional Wiper blades, along with centrifugal force, resulting from the rotation of the plate, then create a thin film by distributing the feed, optimally evenly, over the wall. Due to reduced pressure in the plate chamber and the resulting increase in surface area, the volatile components readily evaporate. The remaining “pure” solid is pushed to the sides by the blades and collected.

The feed is typically in the form of an oil which is obtained by removing the solvent in which OH-MBSG-XY (particularly OH-MBSG) and/or 19 OH-XYPO (particularly 19 OH-TBPO) is in. The feed can also be in the form of a solution. The solvent is typically removed in an evaporator, which leaves the oil (without solvent). In principle, in a scale-up apparatus, these two operations (evaporation of solvent and then purification of the oil) can be done in the TFE. There can be a first rotating distributor plate, above a second plate, and the first and second plates can be heated at different temperatures.

In one embodiment the OH-MBSG-XY (particularly OH-MBSG) is purified by the TFE method. In this method OH-MBSG-XY (particularly OH-MBSG) is fed into the thin film evaporator, and the evaporation is performed at a temperature of about 130° C. to about 200° C., more preferably of about 150° C. to about 160° C. Preferably, the evaporation is performed under a pressure of about 0 mbar to about 15 mbar, more preferably of about 0.5 mbar to about 5 mbar, yet more preferably of about 0.97 mbar to about 1.2 mbar.

Preferably, the OH-MBSG-XY (particularly OH-MBSG) obtained by the thin film evaporation method of the invention has a purity of at least about 95.5%, more preferably of at least about 98.4%, and even more preferably of at least about 99.5% area by GC. Preferably, the obtained OH-MBSG has an assay purity of at least about 98.4%, more preferably of at least about 99%, and most preferably of at least about 100% w/w.

The present invention provides OH-MBSG-XY (particularly OH-MBSG) having a purity of at least about 90%, more preferably of at least about 95%, and even more preferably of at least about 98% area by GC. Preferably, OH-MBSG-XY (particularly OH-MBSG) has a purity of at least about 95.5%, more preferably of at least about 98.4%, and even more preferably of at least about 99.5% area as measured by GC. Preferably, the OH-MBSG-XY (particularly OH-MBSG) has an assay purity of at least about 98.4%, more preferably of at least about 99%, and most preferably of at least about 100% w/w.

In one embodiment, the 19 OH-XYPO (particularly 19 OH-TBPO) is purified by the TFE method. In this method 19 OH-XYPO (particularly 19 OH-TBPO) is fed into the thin film evaporator, and the evaporation is performed at a temperature of about 130° C. to about 200° C., more preferably of about 150° C. to about 160° C. Preferably, the evaporation is performed under a pressure of about 0 mbar to about 15 mbar, more preferably of about 0.97 mbar to about 1.2 mbar.

Preferably, the OH-MBSG-XY (particularly OH-MBSG) and/or 19 OH-XYPO (particularly 19 OH-TBPO) obtained by the thin film evaporation method of the invention has a purity of at least about 95.5%, more preferably of at least about 98.4%, and even more preferably of at least about 99.5% area as measured by GC. Preferably, the obtained 19 OH-TBPO has an assay purity of at least about 98.4%, more preferably of at least about 99%, and most preferably of at least about 100% w/w.

The present invention provides a process of purifying OH-MBSG-XY (particularly OH-MBSG) and/or 19 OH-XYPO (particularly 19 OH-TBPO) and further converting them to Rosuvastatin.

The 19 OH-XYPO (particularly 19 OH-TBPO) can be prepared by a process comprising combining a compound OH-MBSG-XY (particularly OH-MBSG, having the following formula:

dimethylmethylphosphonate (DMMP), and a base capable of making a carbanion on DMMP, as exemplified in the scheme provided below:

wherein M is the metal counter ion of the base. Similarly 19 OH-XYPO can be prepared from OH-MBSG-XY.

The process can be carried out by dissolving DMMP in an organic solvent that is inert to a strong base, and adding dropwise or slowly a base that is sufficiently strong to produce a carbanion. Examples of such bases include LDA, sodium or lithium salts of Hexamethyldisilazane, sec-BuLi, tert-BuLi, NaH, KH, KtBuO, NaBuO, and C₄ to C₁₀ alkyl lithium. Preferably, the organic solvent is selected from the group consisting of: dimethoxyethane (“DME”), hexane, methylene chloride tetrahydrofuran (“THF”) and dioxane. More preferably, the organic solvent is THF, most preferably, dry THF (contains less than 2% water by volume). The solution can be cooled, such as to a temperature of about −50° C. to about −100° C., more preferably, to a temperature of about −75° C.

The base capable of making a carbanion on DMMP is preferably BuLi. Preferably, n-BuLi is added to the solution to obtain a reaction mixture. The reaction mixture can be maintained at a temperature of about −50° C. to about −100° C. More preferably, the reaction mixture is maintained at a temperature of about −70° C. to about −100° C. Preferably, n-BuLi is dissolved in hexane.

A base is used to allow formation of the carbanion reaction to occur. Preferably, the base after reaction provide a metal cation (M+) that is selected from the group consisting of lithium, sodium, potassium and cesium. More preferably, M+ is lithium to the base used for the preparation of the phosphonate.

OH-MBSG-XY (particularly OH-MBSG) can be combined with the reaction mixture in 4 portions. Preferably, OH-MBSG-XY (particularly OH-MBSG) is added in intervals of about 5 minutes to about 60 minutes, more preferably, in intervals of about 30 minutes on gram scale.

Prior to the addition of OH-MBSG-XY (particularly OH-MBSG), the reaction mixture can be stirred. The stirring can be done at a temperature of about −50° C. to about −100° C., more preferably, at a temperature of about −70° C. to about −75° C. The stirring can be for about 1 hour to about 6 hours, more preferably, for about 3 hours.

The reaction mixture can be washed to remove impurities. The washing can be with the same solvent used during the process.

After a washing step, if carried out, the reaction mixture can be stirred. The stirring is at a temperature of about −50° C. to about −100° C. Preferably, at a temperature of about −70° C. to about −75° C. Preferably, the stirring is for about 2 hours.

The reaction mixture can be quenched by adding an agent that has an available proton. The quenching may be done using water, organic acid or inorganic acid. Preferably, the quenching is with AcOH and EtOAc. The reaction mixture can be heated to bring the temperature to about −10 to about 30° C., such as about room temperature or a temperature of about 20° C., before separation. Water can be added to the heated reaction mixture to obtain a two phase system in order to perform the extraction of 19 OH-XYPO (particularly 19 OH-TBPO).

For extraction, the two phases are separated. The aqueous phase is extracted. The extraction can be done with polar solvents such as CH₂Cl₂, Diethylcarbonate, Methyl ethyl ketone, Methyl iso-butyl ketone, cyclopenthylmethylether, t-buteyl methyl ether, diethyl ether, diisopropylether, more preferably with EtOAc (ethyl acetate).

Optionally, the organic layer is dried and filtered. Preferably, the drying is done with dehydrating reagent or molecular sieves, more preferably, with a dehydrating reagent. Preferably, the dehydrating reagent is sodium sulfate (Na₂SO₄) or magnesium sulfate (MgSO₄), more preferably Na₂SO₄.

The obtained dried and filtered layer is further concentrated to obtain a residue of 19 OH-XYPO (particularly 19 OH-TBPO). Preferably, the concentration is under a pressure of less than one atmosphere, or a pressure of less than 100 mmHg, such as in a vacuum. Preferably, the concentration is done by vacuum distillation. Preferably, the vacuum distillation is done whilst heating, such as to a temperature of about 20° C. to about 90° C.

Preferably, the obtained non protected hydroxyl group intermediate, 19 OH-XYPO (particularly 19 OH-TBPO), is further purified by a thin film evaporator. In a large scale apparatus, both concentrations of 19 OH-XYPO (particularly 19 OH-TBPO) after extraction and purification could be performed in a TFE.

19 OH-XYPO (particularly 19 OH-TBPO) obtained by the processes of the invention may be further used to prepare rosuvastatin and pharmaceutically accepted salts thereof, for example, according to the procedures described in PCT publication No. WO 06/091771.

The 19 OH-XYPO (particularly 19 OH-TBPO), obtained, optionally by the thin film evaporation purification, can be converted to TB21 (or another ester) by a Wittig-Horner reaction. The process for preparing compound TB21 by a Wittig-Horner reaction comprises combining 19 OH-TBPO, FPP-aldehyde and a base,

a

Prior to the process, 19 OH-XYPO (particularly 19 OH-TBPO) can be dissolved in a dry solvent (contain less than 2% water by volume). Examples of dry solvents include, but are not limited to, ethereal solvents such as tetrahydrofuran (“THF”), dioxane, dimethoxyethane (“DME”), aromatic solvents such as toluene, chlorinated solvents and acetonitrile. More preferably, the solvent is dry THF. The solution can be cooled, such as to a temperature of about −20° C. to about 10° C., more preferably to about 0° C.

Suitable bases for the Wittig-Horner reaction, include but are not limited to, metal hydrides, MOMe, MOH, MOtBu, M₂CO₃, wherein M can be sodium, potassium, lithium or cesium, BuLi or other lithiated bases, DBU (1,8-diazabicyclo[5.4.0]undec-7-ene), and DABCO (diazabicyclo[2.2.2]octane). Preferably, the base is KOtBu. The base is preferably added to the cooled solution to obtain a reaction mixture. The base can be added under stirring. The reaction mixture can be stirred at a temperature of about −20° C. to about 40° C., more preferably at about 0° C. The reaction mixture can be further stirred. The stirring can be for about 1 minute to about 1 hour, more preferably for about 15 minutes.

In one embodiment, FPP-aldehyde is added to the reaction mixture. After the addition of FPP-aldehyde, the reaction mixture can be stirred, such as at a temperature of about 0° C. to about 60° C., more preferably at about 40° C. The mixture can be stirred for about 1 hour to about 12 hours, such as about 7 hours.

After completion of the reaction, the reaction can be quenched, such as by using an acid, including AcOH (acetic acid). The reaction mixture can be optimized for recovery of the product, by adding water (and optionally brine) and a water immiscible organic solvent such as ethyl acetate to obtain two phases.

The phases can be then separated. The organic phase can be washed such as with water or saturated bicarbonate and brine. In one embodiment, the washing is done with saturated bicarbonate and brine.

Following the phases separation, the remaining solvent is removed to obtain TB21. Preferably, the removal of the solvent is under pressure of less than one atmosphere, such as vacuum (less than 100 mmHg).

In one embodiment, the compound TB21:

is prepared by a process comprising combining OH-MBSG having the following formula:

DMMP and a base which is capable of making a carbanion on DMMP to obtain a non protected hydroxyl group intermediate 19 OH-TBPO having the following formula:

and combining the obtained 19 OH-TBPO with FPP-aldehyde and a base.

TB21 obtained by the processes of the invention may be further converted to rosuvastatin and pharmaceutically accepted salts thereof. The conversion may be done according to PCT publication No. WO 06/091771 and according to US RE37,314. The procedure described in PCT publication No. WO 06/091771 includes converting TB21 to rosuvastatin through the intermediate TBRE. TBRE is obtained by a reduction of the intermediate TB21 according to the scheme provided below:

This process can be performed using diethylmethoxyborane in THF and sodium borohydride. Rosuvastatin may be obtained upon saponification of TBRE according to the scheme provided below:

The processes of the present invention may be illustrated in the following scheme:

Rosuvastatin obtained by the processes of the invention may be further converted to a pharmaceutically acceptable salt of rosuvastatin, preferably the calcium salt. [See e.g. U.S. Pat. No. 5,260,440]. The process of converting rosuvastatin into its pharmaceutically acceptable salt includes contacting rosuvastatin with calcium hydroxide, or with a stronger base such as sodium hydroxide. The base is preferably combined dropwise with a reaction mixture of rosuvastatin at a suitable temperature, such as a temperature of about 25° C.±5° C. The reaction mixture may be washed with a suitable water immiscible organic solvent. Suitable water immiscible organic solvents include, but are not limited to, hydrocarbons; preferably the water immiscible organic solvent is toluene. The water immiscible organic solvent may be removed by phase separation. Remaining water immiscible organic solvent may be removed by distillation of the reaction mixture, preferably at a temperature of about 40° C. to about 45° C. under reduced pressure (below about 50 mmHg).

Column & Packing: DB-17 30m×0.53 mm 1 μm film thickness

The reaction mixture may then be combined with an alkali metal, including a source of calcium such as calcium chloride or calcium acetate, to form the salt of rosuvastatin. [See e.g. U.S. Pat. No. 6,777,552]. For example, calcium chloride may be added dropwise to a reaction mixture of rosuvastatin at a suitable temperature, such as a temperature of about 35° C. to about 45° C., and preferably at about 40° C., over a period of about thirty to about ninety minutes. Active carbon may be combined with a reaction mixture of rosuvastatin to remove impurities from the reaction mixture. If active carbon is used during the conversion of rosuvastatin into its pharmaceutically acceptable salt, the active carbon may be used before or after contacting rosuvastatin with an alkali metal.

The conversion of rosuvastatin into its pharmaceutically acceptable salt may also include filtering the reaction mixture. The reaction mixture may be filtered, such as with Synter and Hyflo®, before or after washing with a water immiscible organic solvent.

Having thus described the invention with reference to particular preferred embodiments and illustrative examples, those in the art can appreciate modifications to the invention as described and illustrated that do not depart from the spirit and scope of the invention as disclosed in the specification. The Examples are set forth to aid in understanding the invention but are not intended to, and should not be construed to, limit its scope in any way. Absent statement to the contrary, any combination of the specific embodiments described above are consistent with and encompassed by the present invention.

Instrumental:

Wiped Film Evaporator made by Pope. 0.02 m2 heat transfer area, 50 mm diameter, made in glass with three Teflon wipers

GC Method:

Injector temperature 180° C. Detector temperature 300° C. Oven temperature 40° C. for 3 minutes, than 20° C./minute up to 160° C., than 160° C. for 10 minutes, than 10° C./minute up to 210° C., than 210° C. for 10 minutes, than 20° C./minute up to 270° C. for 10 minutes. Injection volume 1.0 μl Flow 10 ml/min Helium at 40° C. Mode Constant flow Split ratio 1:10 Detector FID Diluent Acetonitrile

Standard Solution Preparation

Weigh accurately 20 mg of 19TBPO standard into 10 ml volumetric flask, dissolve and bring to volume with Diluent.

Sample Solution Preparation

Weigh accurately 20 mg of 19TBPO sample into 10 ml volumetric flask, dissolve and bring to volume with Diluent.

Procedure

Inject the standard and sample solutions continuing the chromatogram up to the end of gradient.

EXAMPLES Example 1 Preparation of 19 OH-TBPO

DMMP (25.57 g) was dissolved in dry THF (140 mL) and the solution was cooled to −75° C. n-BuLi (2.5M in hexane, 73.3 mL) was added dropwise, keeping the temperature below −70° C. The mixture was stirred at −70-75° C. for 3 h. Hydroxy-MBSG (10 g) was added in 4 portions every half an hour. THF (10 mL) was used to wash traces of hydroxy MBSG from the syringe. After stirring for 2 h at −70-75° C., the mixture was quenched with AcOH (12 mL) and EtOAc (100 mL). The mixture was heated to 20° C. and water (100 mL) was added. Layers were separated and the water layer was extracted with EtOAc (100 mL, 4 times). Combined organic layers were dried over Na₂SO₄, filtered and concentrated under vacuum. The residue contained more than 30% of DMMP, which was removed by vacuum distillation (3 mbar) upon heating of the residue to 80-90° C. The residue (12.1 g) contained 81.2% 19 OH-TBPO (yield 69%).

¹H NMR (300 MHz, CDCl₃): δ 1.40 (s, 9H), 2.85 (d, 2H, J=6 Hz), 2.40 (d, 2H, J=6 Hz), 3.10 (d, 2H, J=23 Hz), 3.75 (d, 6H), 4.50 (m, 1H) (approximate).

Hydroxy-MBSG (OH-MBSG) can be obtained by enzymatic reaction of dimethylhydroxyglutarate and esterification according to WO 03/087112, incorporated by inference.

Example 2

20 g 19-OHTBPO residue (purity GC 63.4%) is purified by thin film evaporator (TFE) at 150° C. under 1.2 mbar vacuum to get 11.6 g 19-OHTBPO (Purity GC 95.5% area, assay 98.4% w/w).

Example 3 Preparation of TB21 from 19 OH-TBPO

Solution of 19 OH-TBPO (2.17 g, assay 92%) in THF (10 mL) was cooled to 0° C. KOtBu (0.67 g) was added under stirring. The mixture was stirred at 0° C. for 15 min and FPP-aldehyde (1.51 g) was added. The mixture was stirred at 40° C. for 7 h and quenched with AcOH (0.15 mL). Brine (15 mL) and EtOAc (30 mL) were added. Phases were separated. The organic phase was washed with saturated bicarbonate solution (15 mL) and brine (15 mL). The solvent was removed under vacuum, resulting in crude TB-21 (2.99 g, assay 46%, yield 60%).

Example 4 Conversion of Compound TBRE into Rosuvastatin Ca with Extraction in

Toluene

A 1 L reactor equipped with a mechanical stirrer was charged with EtOH (300 mL), water (90 ml), and 22TB (60 g), forming a reaction mixture. NaOH (47% 1.2 eq, 11.4 g) was added dropwise to the reaction mixture at RT. The reaction mixture was stirred at about RT for two hours. The reaction mixture was filtered under reduced pressure with Synter and Hyflo® to eliminate the small particles present. Water (420 ml) was added to the reaction mixture.

The mixture was then extracted with toluene (3000 mL) and stirred at RT for half an hour. An aqueous phase formed and was isolated. The aqueous phase was concentrated under reduced pressure at 40° C. to half of the volume. Half of the remaining aqueous phase was transferred to a 500 mL reactor and water (110 mL) was added, creating a solution. The solution was stirred at RT for 5 minutes. Ca(OAc) (8.8 g) was added dropwise to the solution over 117 min. at RT. The solution was stirred at RT for 1 hour, filtered, and washed with 60 mL of water, yielding a powdery compound (26 g, 94%). 

1. A compound, 19 OH-XYPO, of the following formula:

wherein X is O, N, or S, and Y is selected from the group consisting of: a C₁-C₄ alkyl, C₆ to C₁₂ aryl, and C₆ to C₁₂ alkyl aryl group.
 2. The compound of claim 1, wherein the compound is:


3. The compound of claim 1, wherein the compound has a purity of at least about 95.5% area as measured by GC.
 4. The compound of claim 3, wherein the compound has a purity of at least about 98.4% area as measured by GC.
 5. The compound of claim 4, wherein the compound has a purity of at least at least about 99.5% area as measured by GC.
 6. The compound of claim 1, wherein the compound has an assay purity of at least about 98.4% w/w.
 7. The compound of claim 6, wherein the compound has an assay purity of at least at least about 99% w/w.
 8. The compound of claim 7, wherein the compound has an assay purity of at least about 100% w/w.
 9. A process for preparing compound of claim 1 comprising combining compound, 19-OH-MBSG-XY, having the following formula:

wherein X is O, N, or S, and Y is selected from the group consisting of: a C₁-C₄ alkyl group, C₆ to C₁₂ aryl, and C₆ to C₁₂ alkyl aryl with dimethylmethylphosphonate (DMMP) and a base which is capable of making a carbanion on DMMP.
 10. The process of claim 9, wherein the compound is:


11. A process for preparing rosuvastatin or a pharmaceutically acceptable salt thereof comprising converting compound obtained by the process of claim 9 to rosuvastatin or a pharmaceutically accepted salts thereof.
 12. The process of claim 9, wherein the process comprises combining OH-MBSG, dimethylmethylphosphonate (DMMP) and a base which is capable of making a carbanion on DMMP to obtain a non protected hydroxyl group intermediate 19 OH-TBPO; and combining the obtained 19 OH-TBPO with FPP-aldehyde and a base.
 13. A process for preparing compound TB21

comprising converting compound obtained in claim 9 by a Wittig-Horner reaction to compound TB21.
 14. A process for preparing rosuvastatin or a pharmaceutically acceptable salt thereof comprising converting TB21 prepared in claim 13 to rosuvastatin or a pharmaceutically acceptable salt.
 15. A compound, 19-OH-MBSG-XY, of the following formula:

wherein X is O, N, or S, and Y is selected from the group consisting of: a C₁-C₄ alkyl, C₆ to C₁₂ aryl, and C₆ to C₁₂ alkyl aryl group, wherein the compound has a purity of at least about 95.5% as measured by GC.
 16. The compound of claim 15, wherein the compound is:


17. The compound of claim 15, wherein the compound has a purity of at least about 98.4% area as measured by GC.
 18. The compound of claim 17, wherein the compound has a purity of at least at least about 99.5% area as measured by GC.
 19. The compound of claim 15, wherein the compound has an assay purity after purification of at least about 98.4% w/w.
 20. The compound of claim 19, wherein the compound has an assay purity after purification of at least at least about 99% w/w.
 21. The compound of claim 20, wherein the compound has an assay purity after purification of at least about 100% w/w.
 22. A process for preparing compound, 19 OH-XYPO, of the following structure:

wherein X is O, N, or S, and Y is selected from the group consisting of: a C₁-C₄ alkyl, C₆ to C₁₂ aryl, and C₆ to C₁₂ alkyl aryl group, comprising combining compound of claim 15 with dimethylmethylphosphonate (DMMP) and a base which is capable of making a carbanion on DMMP.
 23. The process of claim 22, wherein the base is LDA, sodium or lithium salts of Hexamethyldisilazane, sec-BuLi, tert-BuLi, NaH, KH, KtBuO, NaBuO, and C₄ to C₁₀ alkyl lithium.
 24. The process of claim 22, wherein an organic solvent is used that is selected from the group consisting of: dimethoxyethane (“DME”), hexane, methylene chloride tetrahydrofuran (“THF”) and dioxane.
 25. The process of claim 24, wherein the organic solvent is THF.
 26. The process of claim 22, wherein combining is carried out at a temperature of about −50° C. to about −100° C.
 27. The process of claim 22, wherein the base is BuLi.
 28. The process of claim 22, wherein the compound is:


29. A process for preparing rosuvastatin or a pharmaceutically acceptable salt thereof comprising converting compound obtained by the process of claim 22 to rosuvastatin or a pharmaceutically accepted salts thereof.
 30. A process for preparing compound TB21

comprising converting compound obtained in claim 22 by a Wittig-Horner reaction to compound TB21.
 31. The process of claim 30, wherein the process comprises combining OH-MBSG, dimethylmethylphosphonate (DMMP) and a base which is capable of making a carbanion on DMMP to obtain a non protected hydroxyl group intermediate 19 OH-TBPO; and combining the obtained 19 OH-TBPO with FPP-aldehyde and a base.
 32. A process for preparing rosuvastatin or a pharmaceutically acceptable salt thereof comprising converting TB21 prepared in claim 30 to rosuvastatin or a pharmaceutically acceptable salt.
 33. A process for purifying a one or more of rosuvastatin intermediates 19 OH-XYPO of formula:

or OH-MBSG-XY of formula:

wherein X is O, N, or S, and Y is selected from the group consisting of: a C₁-C₄ alkyl, C₆ to C₁₂ aryl, and C₆ to C₁₂ alkyl aryl group, comprising applying a force under pressure of less than one atmosphere to increase surface area of a feed containing the intermediate, thereby providing the intermediate in purified form.
 34. The process of claim 33, wherein the process comprises feeding the intermediate to a thin film evaporator.
 35. The process of claim 34, wherein the process comprises feeding the intermediate to a thin film evaporator with wiper blades.
 36. The process of claim 33, wherein the intermediate is 19 OH-XYPO having the formula:


37. The process of claim 33, wherein the intermediate is 19 OH-TBPO having the formula:


38. The process of claim 33, wherein the intermediate is OH-MBSG-XY having the formula:


39. The process of claim 33, wherein the intermediate is OH-MBSG having the formula:


40. The process of claim 33, wherein the process is carried out at a temperature of about 130° C. to about 200° C.
 41. The process of claim 40, wherein temperature is about 150° C. to about 160° C.
 42. The process of claim 33, wherein the process is carried out at a pressure e of about 0 mbar to about 15 mbar.
 43. The process of claim 42, wherein the pressure is about 0.97 mbar to about 1.2 mbar.
 44. The process of claim 33, wherein the intermediate after purification has a purity of at least about 95.5% area as measured as measured by GC.
 45. The process of claim 44, wherein the intermediate after purification has a purity of at least about 98.4% area as measured by GC.
 46. The process of claim 45, wherein the intermediate after purification has a purity of at least at least about 99.5% area as measured by GC.
 47. The process of claim 33, wherein the intermediate has an assay purity after purification of at least about 98.4% w/was measured by GC.
 48. The process of claim 47, wherein the intermediate has an assay purity after purification of at least at least about 99% w/was measured by GC.
 49. The process of claim 48, wherein the intermediate has an assay purity after purification of at least about 100% w/was measured by GC.
 50. The process of claim 33, wherein the obtained purified OH-MBSG-XY is further converted to 19 OH-XYPO.
 51. A process for preparing rosuvastatin or a pharmaceutically acceptable salt thereof comprising purifying OH-MBSG-XY as in claim 33, and converting it to rosuvastatin or a pharmaceutically acceptable salt.
 52. A process for preparing compound TB21

comprising converting compound obtained in claim 33 by a Wittig-Horner reaction to compound TB21.
 53. A process for preparing rosuvastatin or a pharmaceutically acceptable salt thereof comprising purifying 19 OH-XYPO as in claim 33, and converting it to rosuvastatin.
 54. A process for preparing rosuvastatin or a pharmaceutically acceptable salt thereof comprising, first purifying OH-MBSG-XY as in claim 33 and using the purified OH-MBSG to synthesize 19 OH-XYPO, followed by purification of 19 OH-XYPO, as in claim 33 and conversion of purified 19 OH-XYPO to rosuvastatin or a pharmaceutically acceptable salt thereof.
 55. The process of claim 54, wherein 19 OH-XYPO is prepared by combining OH-MBSG-XY with a base, a solvent and DMMP.
 56. The process of claim 55, wherein an organic solvent is used that is selected from the group consisting of: dimethoxyethane (“DME”), hexane, methylene chloride tetrahydrofuran (“THF”) and dioxane.
 57. The process of claim 56, wherein the solvents is THF.
 58. The process of claim 55, wherein the base is BuLi.
 59. A process for preparing compound TB21:

comprising combining OH-MBSG having the following formula:

DMMP and a base which is capable of making a carbanion on DMMP to obtain a non protected hydroxyl group intermediate 19 OH-TBPO having the following formula:

and combining the obtained 19 OH-TBPO with FPP-aldehyde and a base. 